On the status of Ghostbusters 3, courtesy of The Telegraph, Aykroyd said:

“At this point it’s in suspended animation. The studio, the director Ivan Reitman, and Harold Ramis feel there must be a way to do it, but Bill Murray will not do the movie.”

On why Murray is reluctant to take part in Ghostbusters 3:

“He doesn’t want to be involved. He’s got six kids, houses all over America. He golfs in these tournaments where they pay him to turn up and have a laugh. He’s into this life and living it. I know we’d have a lot of fun [but] I can’t be mad at him. He’s a friend first, a colleague second. We have a deep personal relationship that transcends business and he doesn’t want to know.”

Aykroyd says he isn’t angry, but there appears to be some frustration on his part regardless of his friendship with Bill Murray. The “houses all over America” bit seems particularly irrelevant. On whether or not he wants to recast Peter Venkman, Aykroyd said:

“We’re not going to do a movie that exploits the franchise. The script has to be perfect. I’m the cheerleader, but I’m only one voice in the matter. It’s a surety that Bill Murray will not do the movie, however there is still interest from the studio.”

Unfortunately, there was a distinct lack of a “No, we will not be replacing Bill Murray,” anywhere in that statement. While there are almost certainly Ghostbusters fans out there interested in seeing a threequel, there are no doubt far fewer fans interested in a sequel sans Bill Murray. That’s because the original would not be a classic without him, just like any sequel will automatically be viewed by many as diluted product.

It’s science, really: The less Bill Murray a film has, the less awesome it is.

Bill Murray in Wes Anderson's 'Moonrise Kingdom'

Dan Aykroyd and everyone interested in making Ghostbusters 3 will likely need Bill Murray (who owns some of the rights) to sign off on the threequel before it can become a reality. That being the case, I (and I’m sure others) hope he holds out in perpetuity.